In this project I hope toidentify to species the streptococci isolated from odontogneic infections, since most published reports on the bacteriology of these infections identify other bacteria but not all the streptococci. At the same time I will identify the othe predominant bacteria. Better identification of the streptococci is needed in order to find if particular species are associated with such infectins, with particluar lesions or with particular species of predominant anaerobes found in the same lesions. Specimens from odontogenic infections are to be collected by the clinical dental staff in a manner which minimizes contamination by mucosal bacteria. Control specimens from the oral cavity will also be collected. These specimens will be cultured by strickly anaerobic methods on enriched agar media. Relative numbers of the predominant bacteria will be assessed and representatives of each type picked for identification, mainly by mode of carbohydrate metabolism. It has been suggested that odontogenic infections are synergistic infections, that is more than one species of bacteria are necessary to initiate the lesion. Therefore I wish to test the fresh isolates in pairs to see if any interactions between the streptococci and predominant non-streptococci can be demonstrated in culture. This is a screening project. If any associations or interactions are found which might be significant I hope that in future they can be analyzed further and tested in tissue culture or experimental animals. This may be one step towards an understanding of theetiology of these infections which cause considerable morbidity and occasional mortality.